LEMPA - Standalone MCU programmer for RPi

LEMPA is a combination of software and hardware that brings modern CI/CD practices to firmware flasging. Key features:

• Fully open source hardware and software
• No need for a computer, screen, or keyboard
• LEMPA will fetch latest versions from cloud / local network automatically
• Embedded web based 2-way serial monitor
• Support for mulitiple controllers including the popular ATMega, ATTiny, and ESP
• Web based interface
• RESTful API for automation
• Multi profile
• Plugin based architecture that can used for automatic testing, embedding unique serial number etc.

Click image for short video:

LEMPA is composed of 3 parts:

Hardware: Raspberry PI HAT

A custom PCB that contains all the relevant connections required to program:

• ATMega328 (including external oscillator)
• ATTiny
• ESP8266
• Arduino mini pro
• Any other ATMega controller via connector

The board also includes:

• LEDs for visual status (ready, downloading, programing, success, and error)
• Jumper to define which profile to use.
• LED for testing
• Program / download button. Short click to program the MCU, long click to download latest version of the BINs from cloud / local network / shared folder.

Software

The software reads the different profiles and orchestrates the process of downloading new BINs and programming

Installation instructions

1. Download the software and extract it
2. Install avrdude if needed sudo apt-get install avrdude
3. Install prequisites: sudo apt-get install libopenjp2-7 and sudo apt-get install libtiff5
4. Install required libraries pip3 install -r requirements.txt
5. Make sure profiles.json reflects your environment
6. python3 program.py or python3 program.py <profile id>
7. Make sure you enable RPi interfaces: SPI, I2C, and Serial

Configuration: profiles.json

The configuration file can contain as many profiles as required.

  {
    "id": "blinklocal",
    "type": "bin",
    "jumper" : 1,
    "device": "m328p",
    "programmer": "linuxspi",
    "bins": [
      {
        "method": "local",
        "name": "blinklocal"
      }
    ],
    "fuses": {
      "lfuse": "0xF7",
      "hfuse": "0xD6",
      "efuse": "0xFD",
      "lock": "0xFF"
    },
    "plugins": [
      {
        "name": "serialinjector",
        "conf": {
          "serialSpeed": 38400,
          "fields": [
            {
              "id": "blinkrate",
              "value": 5,
              "title": "Blink rate in 100ms. For exampe value of 5 means 500ms off, 500ms on",
              "type": "byte"
            }
          ]
        }
      }
    ]

  },
...
]

• id Unique ID for the profile
• type bin or composite. Composite allows for multiple profile programming, one after another.
• jumper optional If specified, and the relevant profile is chosen with a physical jumper, this profile will be used if none was specified as part of command line parameter.
• device Type of device to program. Not required for ESP. See AVRDude for list of devices
• autodetect If set to true, system will start programming as soon as it detects chip (does not work ESP)
• bins List of bins to upload. For ATMega only one bin is required. For ESP multiple bins can be specified to support SPIFFS Bin method can be one of the following:

• plugins System support a simple web server with the ability to send data to the ATMega via serial. This allows for parameter tweaking and QA.

Web Interface

Once LEMPA is up and running, It exposes web UI via port 8080 that allows:

• Live view of system actions
• Full working 2 way serial monitor. ATMega328 is connected by default to RPi serial0. External boards can be connected via dedicated headers on the HAT
• Operation log
• System control

Contact

Please contact me at [email protected] with any comments